%0 Journal Article
%A Acton, W. Joe F.
%A Schallhart, Simon
%A Langford, Ben
%A Valach, Amy
%A Rantala, Pekka
%A Fares, Silvano
%A Carriero, Giulia
%A Tillmann, Ralf
%A Tomlinson, Sam J.
%A Dragosits, Ulrike
%A Gianelle, Damiano
%A Hewitt, C. Nicholas
%A Nemitz, Eiko
%T Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy
%J Atmospheric chemistry and physics
%V 16
%N 11
%@ 1680-7324
%C Katlenburg-Lindau
%I EGU
%M FZJ-2016-03691
%P 7149 - 7170
%D 2016
%X This paper reports the fluxes and mixing ratios of biogenically emitted volatile organic compounds (BVOCs) 4 m above a mixed oak and hornbeam forest in northern Italy. Fluxes of methanol, acetaldehyde, isoprene, methyl vinyl ketone + methacrolein, methyl ethyl ketone and monoterpenes were obtained using both a proton-transfer-reaction mass spectrometer (PTR-MS) and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) together with the methods of virtual disjunct eddy covariance (using PTR-MS) and eddy covariance (using PTR-ToF-MS). Isoprene was the dominant emitted compound with a mean daytime flux of 1.9 mg m−2 h−1. Mixing ratios, recorded 4 m above the canopy, were dominated by methanol with a mean value of 6.2 ppbv over the 28-day measurement period. Comparison of isoprene fluxes calculated using the PTR-MS and PTR-ToF-MS showed very good agreement while comparison of the monoterpene fluxes suggested a slight over estimation of the flux by the PTR-MS. A basal isoprene emission rate for the forest of 1.7 mg m−2 h−1 was calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) isoprene emission algorithms (Guenther et al., 2006). A detailed tree-species distribution map for the site enabled the leaf-level emission of isoprene and monoterpenes recorded using gas-chromatography mass spectrometry (GC–MS) to be scaled up to produce a bottom-up canopy-scale flux. This was compared with the top-down canopy-scale flux obtained by measurements. For monoterpenes, the two estimates were closely correlated and this correlation improved when the plant-species composition in the individual flux footprint was taken into account. However, the bottom-up approach significantly underestimated the isoprene flux, compared with the top-down measurements, suggesting that the leaf-level measurements were not representative of actual emission rates.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000378354600030
%R 10.5194/acp-16-7149-2016
%U https://juser.fz-juelich.de/record/811182